Chemical and structural effects of invasive plants on herbivore-parasitoid/predator interactions in native communities

2012 ◽  
Vol 144 (1) ◽  
pp. 14-26 ◽  
Author(s):  
Jeffrey A. Harvey ◽  
Taiadjana M. Fortuna
Keyword(s):  
Invasive Plants ◽  
Structural Effects ◽  
Native Communities ◽  
Predator Interactions

scholarly journals Biotic Resistance of Native Communities and Alien Propagule Pressure are Consistent Predictors of Invasion Success During Grassland Establishment

2021 ◽  
Author(s):  
Sandra Liliana Rojas-Botero ◽  
Johannes Kollmann ◽  
Leonardo H. Teixeira
Keyword(s):  
Invasive Plants ◽  
Biotic Resistance ◽  
Propagule Pressure ◽  
N Fertilization ◽  
Invasion Success ◽  
Native Community ◽  
Environmental Fluctuation ◽  
Native Communities ◽  
Propagule Size ◽  
Key Driver

Abstract Invasive alien plants challenge ecosystems restoration. Thus, understanding factors determining the establishment of invasive plants is crucial to improve restoration outcomes. Some key drivers of invasibility of plant communities have been studied, but results are inconsistent, and combined effects have not been addressed. We investigated the contribution of three drivers of invasion success during early phases of restoration, i.e., biotic resistance, invasive propagule pressure, and environmental fluctuations.We compared the contribution of these drivers in a series of mesocosms experiments using designed grasslands as a model system, and Solidago gigantea as invasive model species. Two grassland communities were designed according to competitive trait hierarchies with different sowing patterns, reflecting variation in biotic resistance. We then manipulated invader propagule pressure and applied different scenarios of environmental fluctuation, i.e., flood, heat, and N fertilization. Alien biomass was considered as proxy for invasion success, while native biomass represented restoration success.There were consistent effects of biotic resistance to S. gigantea invasion via competitive trait hierarchies in the three experiments. Communities dominated by species with high-competition traits were more resistant regardless of environmental fluctuation. Clumped seeding of the native community reduced invasibility, whereas larger invasive propagule size increased invasion. The effects of environmental fluctuation were less consistent and context-dependent, thus playing a secondary role when compared to biological drivers of invasion. Restoration initiatives on grasslands impacted by invasive plants should consider biotic resistance of the restored community as a key driver and the importance of controlling further arrivals of invasive species during community assembly.

scholarly journals Competitive trait hierarchies of native communities and invasive propagule pressure consistently predict invasion success during grassland establishment

2021 ◽  
Author(s):  
Sandra Rojas-Botero ◽  
Johannes Kollmann ◽  
Leonardo H. Teixeira
Keyword(s):  
Invasive Plants ◽  
Biotic Resistance ◽  
Propagule Pressure ◽  
N Fertilization ◽  
Invasion Success ◽  
Native Community ◽  
Environmental Fluctuation ◽  
Native Communities ◽  
Key Driver ◽  
Early Phases

AbstractInvasive non-native plants challenge ecosystems restoration, and understanding the factors that determine the establishment of invasive plants is crucial to improve restoration outcomes. However, the drivers of invasibility of plant communities are not sufficiently clear, and combined effects are not understood. Therefore, we investigated the contribution of the main drivers of invasion success during early phases of restoration, i.e., biotic resistance, invasive propagule pressure, and environmental fluctuations. We compared the contribution of these drivers in a series of mesocosms experiments using designed grasslands as a model system, and Solidago gigantea as invasive model species. Two grassland communities were designed according to competitive trait hierarchies with different sowing patterns, reflecting variation in biotic resistance. We then manipulated invader propagule pressure and applied different scenarios of environmental fluctuation, i.e., flood, heat, and N fertilization. Invasive biomass was considered as proxy for invasion success, while native biomass represented restoration success. There were consistent effects of biotic resistance to S. gigantea invasion via competitive trait hierarchies in the three experiments. Communities dominated by species with high-competition traits were more resistant regardless of environmental fluctuation. Clumped seeding of the native community reduced invasibility, whereas high non-native propagule density increased invasion. The effects of environmental fluctuation were less consistent and context-dependent, thus playing a secondary role when compared to biotic drivers of invasion. Restoration initiatives on grasslands impacted by invasive plants should consider biotic resistance of the restored community as a key driver and the importance of controlling further arrivals of invasive species during community assembly.

the effects of resonance with Jupiter in the system of short-period comets

1974 ◽  
Vol 22 ◽  
pp. 193-203
Author(s):  
L̆ubor Kresák
Keyword(s):  
Structural Effects ◽  
Order Resonance ◽  
Mean Motion ◽  
Short Period ◽  
The Mean ◽  
Compound Effect ◽  
Low Order

AbstractStructural effects of the resonance with the mean motion of Jupiter on the system of short-period comets are discussed. The distribution of mean motions, determined from sets of consecutive perihelion passages of all known periodic comets, reveals a number of gaps associated with low-order resonance; most pronounced are those corresponding to the simplest commensurabilities of 5/2, 2/1, 5/3, 3/2, 1/1 and 1/2. The formation of the gaps is explained by a compound effect of five possible types of behaviour of the comets set into an approximate resonance, ranging from quick passages through the gap to temporary librations avoiding closer approaches to Jupiter. In addition to the comets of almost asteroidal appearance, librating with small amplitudes around the lower resonance ratios (Marsden, 1970b), there is an interesting group of faint diffuse comets librating in characteristic periods of about 200 years, with large amplitudes of about±8% in μ and almost±180° in σ, around the 2/1 resonance gap. This transient type of motion appears to be nearly as frequent as a circulating motion with period of revolution of less than one half that of Jupiter. The temporary members of this group are characteristic not only by their appearance but also by rather peculiar discovery conditions.

Speech-Language Assessment Considerations for American Indian and Alaska Native Children Who Are Dual Language Learners

2017 ◽  
Vol 2 (14) ◽  
pp. 29-40 ◽  
Author(s):  
Christine Vining ◽  
Edgarita Long ◽  
Ella Inglebret ◽  
Megan Brendal
Keyword(s):  
American Indian ◽  
Language Learners ◽  
Alaska Native ◽  
Dual Language ◽  
Linguistic Diversity ◽  
Critical Role ◽  
Language Assessment ◽  
Assessment Process ◽  
Dual Language Learners ◽  
Native Communities

The overrepresentation of American Indian and Alaska Native (AI/AN) children in special education, including children who are dual language learners (DLLs), is a major concern. Speech-language pathologists (SLPs) can play a critical role in reducing this overrepresentation. Using a holistic assessment process that is responsive to the communication patterns of home and community contexts provides a framework for distinguishing actual language disorders from differences associated with cultural and linguistic diversity. This article presents current trends in Native communities that may impact the speech-language assessment process, including a shift from indigenous languages to English and/or Native language revitalization efforts. It also provides a framework for guiding assessment in a manner that considers cultural and linguistic factors in speech-language assessment for AI/AN children who are DLLs.

Track 2.a Introduction

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Sucharita BENIWAL ◽  
Sahil MATHUR ◽  
Lesley-Ann NOEL ◽  
Cilla PEMBERTON ◽  
Suchitra BALASUBRAHMANYAN ◽  
...  
Keyword(s):  
Case Studies ◽  
Local Knowledge ◽  
Ways Of Knowing ◽  
Social Contexts ◽  
Knowledge Systems ◽  
Theoretical Frameworks ◽  
Native Communities ◽  
Cultural Systems ◽  
Local Practices

The aim of this track was to question the divide between the nature of knowledge understood as experiential in indigenous contexts and science as an objective transferable knowledge. However, these can co-exist and inform design practices within transforming social contexts. The track aimed to challenge the hegemony of dominant knowledge systems, and demonstrate co-existence. The track also hoped to make a case for other systems of knowledges and ways of knowing through examples from native communities. The track was particularly interested in, first, how innovators use indigenous and cultural systems and frameworks to manage or promote innovation and second, the role of local knowledge and culture in transforming innovation as well as the form of local practices inspired innovation. The contributions also aspired to challenge through examples, case studies, theoretical frameworks and methodologies the hegemony of dominant knowledge systems, the divides of ‘academic’ vs ‘non-academic’ and ‘traditional’ vs ‘non-traditional’.

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